blood groups of the mantled howler monkey (alouatta palliata).fifty-two howler monkeys were tested for their human-type a-b-o blood groups. all were group b, as shown by the presence of b and h in their saliva, and anti-a in serum. the b-like agglutinogen of their red cells is common to all new world monkey species tested, and is of different origin and significance than their true a-b-o blood group. differences among the b-like agglutinogens of the red cells of howler monkeys, marmosets, rabbits and humans group b were demonstrated, and limited tests have ...1977412971
repeated sedation of the howler monkey (alouatta caraya) with ketamine hydrochloride. 1978416291
urine-rubbing behavior in the mantled howler monkey alouatta palliata.mantled howler monkeys (alouatta palliata) of both sexes and all age classes were observed rubbing urine on the soles of the feet and/or palms of the hands as well as the ventral surface of the tail and, occasionally, the throat. instances of urine-rubbing were often associated with periods of troop movement or times of social stress. intra-troop cohesion may be the primary function of such behavior. other possible function of urine-rubbing are discussed.1975806506
y-autosome translocation in the howler monkey, alouatta palliata.two modal diploid chromosome numbers were encountered in a population sample of howler monkeys, alouatta palliata. the modal diploid number of males was 53, females: 54. karyotypes prepared by g-band and c-band techniques identified a y-auto-some translocation in the males.1975810590
development of falciparum malaria in a panamanian subspecies of howler monkey. 1975812370
in vitro survival of howler monkey (alouatta caraya) and other simian lymphocytes.lymphoid cell cultures from normal howler monkey (alouatta caraya) lymph nodes or peripheral blood were found to survive for over four months. several-fold increase in cell numbers occurred during the first two months of culture. the cells were predominantly of t-cell origin. herpes or c-type virus or viral genomes were not detected in these lymphoid type cultures.1976826637
[characteristics of the absorption surface of the intestinal epithelium of alouatta caraya].electron microscopy of the absorption surface of the jejunal epithelium of the howler monkey alouatta caraya showed the presence of core filaments implanted at the level of the terminal web in the microvilli. these microvilli are 5 to 7 mum long and up to 5 mum thick, their extraordinary development is attributed to a conditioned adaptation of the species to its feeding habits and nature of absorption.1976828283
pneumocystis carinii infections in zoo animals.pneumocystis carinii was found to be present in the lungs of twenty-three zoo animals in the netherlands. the following species were represented: red kangaroo, common tree shrew, senegal-galago, demidoff's-galago, brown howler monkey, woolly monkey, long-haired spider monkey, white-eared marmoset, chimpanzee, three-toed sloth, palm squirrel, red panda, fennec fox, tree hyrax and large-toothed hyrax.19751079994
ape limb bone from the oligocene of ulna attributed to aegyptopithecus zeuxis provides the first evidence for interpreting the locomotor behavior of the earliest apes. the fossil indicates that aegyptopithecus was an arboreal quadruped and that the primitive hominoid locomotor pattern was most nearly analogous, among living primates, to that of alouatta, the howler monkey.19751138369
eosinophilic meningoencephalitis due to angiostrongylus cantonensis as the cause of death in captive non-human primates.fatal eosinophilic meningoencephalitis due to angiostrongylus cantonensis is reported in captive non-human primates. a howler monkey (alouatta caraya) at the audubon park and zoological gardens, new orleans, la, died 21 days after initial clinical symptoms. a white-handed gibbon (hylobates lar) died at the ardastra gardens and zoo, nassau, bahamas, 17 days after onset of symptoms. both had access to free-ranging gastropods within the zoos. these are the first reported cases of natural infection ...19902301708
experimental technique for the conservation of private lands.a community-based sanctuary for the black howler monkey (alouatta pigra) has been established on 18 square miles of riverine forest along the belize river, belize. it is based on voluntary signed pledges by subsistence farmers to abide by management plans for their lands. conservation-education programs which impact favorably on the villagers are being carried out.19883184168
blood clotting in the howler monkey (alouatta caraya). 19684233371
a subcutaneous abscess associated with salmonella typhimurium in a black howler monkey (alouatta villosa). 19714329305
hematologic values of the black spider monkey (ateles fusciceps), red spider monkey (ateles geoffroyi), white face monkey (cebus capucinus), and black howler monkey (alouatta villosa). 19714329310
prenatal dental development in the black howler monkey (alouatta caraya). 19734632074
occlusofacial relationships in the mature howler monkey (alouatta caraya). 19664957120
the chromosome complement of the howler monkey (alouatta caraya, humboldt 1812). 19664959870
the periodontium and periodontal pathology in the howler monkey. 19674960732
odontometric characteristics of the howler monkey (alouatta caraya). 19674964189
the functional anatomy of the lower limb of the howler monkey (alouatta caraya). 19684970511
plasmodium falciparum infection induced in the black spider monkey, ateles fusciceps, and black howler monkey, alouatta villosa. 19704986058
[simian malaria in central brazil: finding of plamodium brazilianum in a howler monkey of the state of mato grosso]. 19704996304
some parasites of the howler monkey of northern argentina. 19665910450
seminoma in a howler monkey (alouatta caraya). 19665949573
aortic mediocalcinosis in a howler monkey (alouatta caraya). 19666006014
dissecting aneurysm of the aorta in a howler monkey (alouatta caraya). 19666007205
rates of fermentative digestion in the howler monkey, alouatta palliata (primates: ceboidea).1. caecal material of wild howler monkeys was analyzed by gas chromatography for evidence of fermentation activity and rates of production and absorption of volatile fatty acids. 2. results showed a high rate of production of acetic acid and lesser production of propionic, butyric and isobutyric acids. the vfa content of the blood was increase in passage through the caecal vascular system. 3. we estimate that howler monkeys may obtain as much as 31% of their required daily energy from fermentati ...19836130881
forelimb musculature and ligaments in ateles, the spider monkey.the forelimb anatomy of ateles, the spider monkey, is a key factor in its locomotor adaptation because of its extensive use of bimanual suspensory locomotion in addition to climbing and quadrupedal walking (mittermeier, 1978; and fleagle and mittermeier, 1980). the detailed description of the muscles and ligaments of the forelimb of ateles provided in this paper can be of considerable use not only to primate morphologists interested in both extant and fossil primates but also to functional anato ...19836650682
density and habitat use of primates at an atlantic forest reserve of southeastern brazil.about 58.3 km of transects were surveyed throughout 21,800 ha of an atlantic forest reserve of southeastern brazil, yielding habitat preference data and density estimates for three of the four primate species present. the densities were calculated using the "fourier series estimator" and were 10.5, 2.2 and 1.2 groups/km2 for callithrix geoffroyi, cebus apella robustus and callicebus personatus personatus, respectively. alouatta fusca fusca although present, was not seen during the survey. c. geo ...19957569145
conservation of sequences between human and gorilla lineages: adp-ribosyltransferase (nad+) pseudogene 1 and neighboring retroposons.the evolution of adp-ribosyltransferase (nad+) pseudogene 1 (adprtp1) was studied among higher primates. when the human pseudogene was used to probe genomic dna from chimpanzee, gorilla, macaque, howler monkey and lemur, a fragment from gorilla produced the most intense hybridization signal. the resultant hybridization pattern indicated a modified pseudogene structure in these primates relative to the human and gorilla loci. sequence comparison of this new dna locus (adprtp1 and surrounding retr ...19957721098
allomaternal care in the black howler monkey (alouatta caraya). 19938188120
habitat, density and group size of primates in a brazilian tropical forest.habitats, population densities and group sizes of 5 primate species (callithrix flaviceps, callicebus personatus personatus, cebus apella nigritus, alouatta fusca clamitans, and brachyteles arachnoides) were estimated, using the method of repeated transect sampling, in an area of montane pluvial forest in eastern brazil (atlantic forest). a. fusca and c. apella had the highest densities in terms of groups and individuals per square kilometer, respectively, while b. arachnoides was least abundant ...19938206419
trichromatic colour vision in new world monkeys.trichromatic colour vision depends on the presence of three types of cone photopigment. trichromacy is the norm for all old world monkeys, apes and humans, but in several genera of new world monkeys, colour vision is strikingly polymorphic. the difference in colour vision between these new and old world primates results form differing arrangements of the pigment genes on the x chromosome. in old world primates the three photopigments required for routine trichromatic colour vision are encoded by ...19968700203
stable isotope ratios indicate diet and habitat use in new world monkeys.this paper demonstrates the use of stable isotope ratios of carbon and nitrogen in animal tissue for indicating aspects of species behavioral strategy. we analyzed hair from individuals representing four species of new world monkeys (alouatta palliata, the mantled howler; ateles geoffroyi, the spider monkey; cebus capucinus, the capuchin; and brachyteles arachnoides, the woolly-spider monkey or muriqui) for delta 13c and delta 15n using previously developed methods. there are no significant diff ...19979185952
conspecific aggression and predation: costs for a solitary mantled howler monkey. 19979212460
contrasting levels of dna polymorphism at the autosomal and x-linked visual color pigment loci in humans and squirrel monkeys.the x-linked color pigment (opsin) locus is known to be highly polymorphic in the squirrel monkey and other new world monkeys. to see whether this is also the case for the autosomal (blue) opsin locus, we obtained 32 squirrel monkey and 30 human blue opsin gene sequences. no amino acid polymorphism was found in either the squirrel monkey sample or the human sample, contrary to the situation at the x-linked opsin locus. this sharp contrast in the level of polymorphism might be due to differences ...19989549095
characterization of microsatellite loci in a new world primate, the mantled howler monkey (alouatta palliata). 19989633106
feeding ecology of the black howler monkey (alouatta pigra) in northern belize.we studied the feeding ecology of the black howler monkey (alouatta pigra) from march 1994 to april 1995 in the community baboon sanctuary in northern belize, central america. activity and diet composition were recorded using continuous focal animal sampling. diet composition was compared with the relative abundance of plant parts eaten by the howlers within the study site. the study animals spent an average of 24.4% of their time feeding, 61.9% resting, and approximately 9.8% traveling. in cont ...19989651649
group size and population density of the black howler monkey (alouatta pigra) in muchukux forest, quintana roo, mexico. 19989751828
the evolution of trichromatic color vision by opsin gene duplication in new world and old world primates.trichromacy in all old world primates is dependent on separate x-linked mw and lw opsin genes that are organized into a head-to-tail tandem array flanked on the upstream side by a locus control region (lcr). the 5' regions of these two genes show homology for only the first 236 bp, although within this region, the differences are conserved in humans, chimpanzees, and two species of cercopithecoid monkeys. in contrast, most new world primates have only a single polymorphic x-linked opsin gene; al ...199910413401
phenolic content and antioxidant activity: a study on plants eaten by a group of howler monkeys (alouatta fusca). 199910800473
oral focal epithelial hyperplasia in a howler monkey (alouatta fusca).oral focal epithelial hyperplasia is a rare and seldom reported disease in animals and humans induced by a papillomavirus. the present report is the first description of this disease in a neotropical primate, a howler monkey (alouatta fusca). the diagnosis was based on gross and microscopic findings. the generic papillomavirus antigen was identified by immunohistochemistry and was found not to be related to any human papillomavirus dna tested by in situ hybridization. this virus is probably a sp ...200011055880
conservation of absolute foveal area in new world monkeys. a constraint on eye size and conformation.the foveal specializations of five new world monkeys, the marmoset, callithrix jacchus; the golden-handed tamarin, saguinus midas niger; the squirrel monkey, saimiri ustius; the capuchin monkey, cebus apella; and the howler monkey, alouatta caraya were compared. although retinal area varies by over a factor of two in these monkeys, the area of the fovea does not covary with retinal area and remains approximately the same absolute size, as measured by the dimensions of the high density region of ...200011251320
timing of births in sympatric brown howler monkeys (alouatta fusca clamitans) and northern muriquis (brachyteles arachnoides hypoxanthus).we monitored the birth patterns of sympatric brown howler monkeys (alouatta fusca clamitans) and northern muriquis (brachyteles arachnoides hypoxanthus) during a 4-yr period from october 1996 to august 2000 at the estação biológica de caratinga, minas gerais, brazil. brown howler monkey births (n = 34) occurred throughout the year, and birth frequencies did not differ between rainy and dry season months. the aseasonal birth patterns of the howler monkeys differed significantly from the dry seaso ...200111668527
survey of the black howler monkey, alouatta pigra, population at the mayan site of palenque, chiapas, mexico.a survey of the population of the black howler monkey (alouatta pigra) present at the mayan site of palenque was conducted during 2000. a total of 911 man/hours, spread over 112 days were spent surveying the 600 ha area of pristine forest at the site for howler troops. we detected the presence of 136 individuals of which 131 were members of 20 troops, the rest were 3 solitary adult males and 2 adult males travelling as a pair. ecological density was estimated at 23 individuals/km(2). mean troop ...200212091747
population of the black howler monkey (alouatta pigra) in a fragmented landscape in palenque, chiapas, mexico.little is known about the population characteristics of alouatta pigra under conditions of forest fragmentation-information that is important to understanding its tolerance to habitat loss. in this work we present data on forest loss and on troop size, age, and sex composition for a population of black howler monkeys existing in the fragmented landscape surrounding the mayan site of palenque, chiapas, mexico. two aerial photos (1:70,000) of the study area (261 km(2)) taken in 1984 and 2001 were ...200212386913
interspecific interaction and predator avoidance behavior in response to tayra (eira barbara) by mantled howler monkeys (alouatta palliata).this paper reports the response of one howler monkey group (alouatta palliata) to a group of potential predators, the tayra (eira barbara). the apparently successful predator avoidance behavior of the monkeys was recorded in detail. we observed a group of four adult tayras moving around the alouatta group displaying a species-typical aggressive behavioral pattern. the two adult females of the howler group successfully chased the tayras away by repeatedly moving closer to the mustelids and even f ...200212426467
molecular systematics and biogeography of the neotropical monkey genus, alouatta.we take advantage of the broad distribution of howler monkeys from mexico to argentina to provide a historical biogeographical analysis on a regional scale that encompasses the entire neotropics. the phylogenetic relationships among 9 of the 10 recognized alouatta species were inferred using three mitochondrial and two nuclear genes. the nuclear gene regions provided no phylogenetic resolution among howler monkey species, and were characterized by very low levels of sequence divergence between a ...200312470939
serologic survey of toxoplasma gondii in noncarnivorous free-ranging neotropical mammals in french guiana.the aim of this study was to determine the frequency of toxoplasma infection in wild mammals, particularly noncarnivorous species, and to identify possible sources of infection for humans. a serological study was conducted that included 310 animals representing 10 species of terrestrial mammals from the same region (primary tropical rain forest inhabited by humans). toxoplasmosis was diagnosed using a direct agglutination test using formalin-treated toxoplasma gondii. the prevalence of antibodie ...200212656126
natural selection on molar size in a wild population of howler monkeys (alouatta palliata).dental traits have long been assumed to be under selection in mammals, based on the macroevolutionary correlation between dental morphology and feeding behaviour. however, natural selection acting on dental morphology has rarely, if ever, been documented in wild populations. we investigated the possibility of microevolutionary selection on dental traits by measuring molar breadth in a sample of alouatta palliata (mantled howler monkey) crania from barro colorado island (bci), panama. the age at ...200312952624
manzanilla virus: a new virus isolated from the blood of a howler monkey in trinidad, w.i. 196013793362
[histochemical study of a hepatic cell pigment of the monkey "alouatta fusca" (primates, mammalia)]. 196114454231
survey of black howler (alouatta pigra) and spider (ateles geoffroyi) monkeys in the mayan sites of calakmul and yaxchilán, mexico and tikal, guatemala.surveys of populations of spider and howler monkeys were conducted at the mayan sites of calakmul and yaxchilán, mexico and tikal, guatemala. the forests in which these sites are found are part of the largest landmass of tropical rain forests present in mesoamerica, encompassing about 4 million ha. triangulation of monkey vocalization combined with ground surveys was used to determine the presence of howler and spider monkey groups. howler monkey mean troop size at these sites varied from 6.6+/- ...200414586803
a case of yellow fever in a brown howler (alouatta fusca) in southern brazil.many brown howlers (alouatta fusca) have died in a 3-month period in a subtropical forest in southern brazil. one was examined after a systemic illness. according to clinical signs, and necropsy and histopathology findings, yellow fever virus (yfv) infection was suspected. tissue sections from liver, kidney, and lymphoid organs were screened by immunohistochemistry for yfv antigens. cells within those tissues stained positively with a polyclonal antibody against yfv antigens (1:1,600 dilution), ...200314667022
loss of olfactory receptor genes coincides with the acquisition of full trichromatic vision in primates.olfactory receptor (or) genes constitute the molecular basis for the sense of smell and are encoded by the largest gene family in mammalian genomes. previous studies suggested that the proportion of pseudogenes in the or gene family is significantly larger in humans than in other apes and significantly larger in apes than in the mouse. to investigate the process of degeneration of the olfactory repertoire in primates, we estimated the proportion of or pseudogenes in 19 primate species by surveyi ...200414737185
wild terrestrial rainforest mammals as potential reservoirs for flaviviruses (yellow fever, dengue 2 and st louis encephalitis viruses) in french guiana.a serological survey for yellow fever virus (yfv), dengue 2 virus (denv-2), and st louis encephalitis virus (slev) was undertaken using a seroneutralization technique in 27 wild forest mammal species (574 individuals) in french guiana. evidence of yellow fever infection was observed in 10 species, with high prevalence recorded in howler monkey (18%) and agouti (20%). antibodies against denv-2 and slev were found sporadically in various species. this potential host diversity and the range of pote ...200415138077
observed case of infanticide committed by a resident male central american black howler monkey (alouatta pigra).although infanticide has been witnessed in other species of howler monkey, and has been inferred for alouatta pigra, an observed case of infanticide has not previously been recorded for this species. here we describe the killing of a 2-week-old infant by the resident male of a small social group in southern belize. the infanticide was witnessed as part of an intensive observational study that began in january 2003. the male was known to have resided in the group for at least 4 months, but it is ...200415300711
a case of pseudo-pregnancy in captive brown howler monkeys (alouatta guariba). 200415486445
testosterone levels of free-ranging resident mantled howler monkey males in relation to the number and density of solitary males: a test of the challenge hypothesis.the challenge hypothesis asserts that testosterone levels and aggression in male adult animals are closely associated with one another in the context of intense reproductive competition, particularly when males challenge one another for the access to females. for mantled howler monkeys (alouatta palliata), the presence of a solitary male in the vicinity of a social group can be considered a threat for the reproductive success of the resident males, as group takeovers by solitary males are follow ...200616182297
possible costs of radio-tracking a young adult female mantled howler monkey (alouatta palliata) in deciduous habitat of costa rican tropical dry forest. 200516468950
habitat fragmentation and effects of herbivore (howler monkey) abundances on bird species richness.habitat fragmentation can alter herbivore abundances, potentially causing changes in the plant community that can propagate through the food web and eventually influence other important taxonomic groups such as birds. here we test the relationship between the density of red howler monkeys (alouatta seniculus) and bird species richness on a large set of recently isolated land-bridge islands in lago guri, venezuela (n = 29 islands). several of these islands host relict populations of howler monkey ...200616634305
light microscopical and ultrastructural characterization of black howler monkey (alouatta caraya) ovarian follicles.the present study describes the morphological characteristics of black howler monkey (alouatta caraya) ovarian follicles. one ovary of an adult healthy black howler monkey was collected and processed for light and electron microscopy. primordial, primary, secondary, tertiary and pre-ovulatory follicles were evaluated for their morphometrical aspects. the ovary of black howler monkey presented a distinct conformation with a uniform distribution of the follicles mostly in the peripheric cortex. th ...200616677216
parasites of free-ranging black howler monkeys (alouatta pigra) from belize and mexico.parasites are important members of the ecological web within which an animal lives, and can be used as indicators of ecosystem health. however, few baseline parasitological data are available for free-ranging animals, particularly for the black howler monkey (alouatta pigra). in this study a total of 283 fecal samples were collected from 50 individually identified a. pigra during 2003 and 2004 and examined for parasites. the samples were processed using standard quantitative centrifugation conce ...200617044010
mitochondrial sequence diversity of the southernmost extant new world monkey, alouatta caraya.variability in mitochondrial dna sequences was analyzed in the howler monkey, alouatta caraya, in order to delineate evolutionary relationships among populations in the most southerly distributed new world monkey. based on new and previously published sequence data, fourteen cytochrome b haplotypes were observed among 33 howlers sampled in argentina, paraguay and brazil, and grouped in two main haplogroups. in northeastern argentina and southern paraguay, new sequence data on 73 specimens sample ...200717126568
epizootics of yellow fever in venezuela (2004-2005): an emerging zoonotic disease.epidemics and epizootics of yellow fever (yf) have been occurring in the border area of eastern colombia and western venezuela since 2003; for this reason many epidemiological control measures were adopted by the ministry of health (moh) trying to prevent their spreading. these activities included monkey deaths surveillance as well as immunization of susceptible individuals with yf vaccine. in this setting, we analyzed epidemiological and epizootical issues related to yf in venezuela during 2004 ...200617135494
first record of amblyomma aureolatum (pallas, 1772) (acari: ixodidae) parasitizing alouatta guariba (humboldt) (primata: atelidae) in southern brazil.a female of amblyomma aureolatum was found on the howler monkey alouatta guariba, in cachoeira do sul, rio grande do sul, southern brazil. this is the first record of this tick species parasitizing this primate species in brazil.200617196126
ocelot (leopardus pardalis) predation on primates in caratinga biological station, southeast brazil.this study demonstrates that ocelots (leopardus pardalis) extensively use primates as a food resource at the caratinga biological station (cbs) in southeast brazil. analysis of 60 fecal samples collected over 4 years revealed predation upon the brown howler monkey (alouatta guariba), the muriqui (brachyteles hypoxanthus), and the brown capuchin monkey (cebus apella). the most frequent items found in the fecal samples analyzed were calomys (n=16) and non-identified aves (n=15), followed by a. gua ...200717330310
fruit diet of alouatta guariba and brachyteles arachnoides in southeastern brazil: comparison of fruit type, color, and seed size.fruit is an important food resource for neotropical primates. in this study i compare the fruit diet of sympatric brown howlers (alouatta guariba) and southern muriquis (brachyteles arachnoides). feeding behavior was studied over 12 months and fruit species consumed were identified and assigned to the categories fruit type, fruit color, and seed size. observed-fruit feeding records were compared with expected records determined from local availability of the fruit of the tree species. i also det ...200817578654
the roaring of southern brown howler monkeys (alouatta guariba clamitans) as a mechanism of active defence of borders.our study aimed to understand the function(s) of roars of southern brown howler monkeys (alouatta guariba clamitans). the study group called almost exclusively on its range borders and preferentially on early mornings, but with no dawn peak. intergroup encounters were associated with 88% of all sessions. predation deterrence and regulation of access to mating partners do not seem compatible with our findings, but more work is needed to reject the latter hypothesis. their roars seem to be related ...200717641481
behavioral effects of introducing pied tamarin (saguinus bicolor) to black howler monkey (alouatta caraya) and white-faced saki (pithecia pithecia) in a zoological park.mixed-species primate exhibits are becoming more common in zoological parks as a means to display a diverse array of animals both more naturalistically and with more economy of space. here, we describe behavioral changes during the introduction process of a pair of pied tamarins (saguinus bicolor) to an established group of black howler monkeys (allouatta caraya) and white-faced saki monkeys (pithecia pithecia). data were collected during six phases, representing introductions among the various ...200818176938
group size and composition influence male and female reproductive success in black howler monkeys (alouatta pigra).it has been argued that grouping patterns might influence the reproductive performance of individuals. increasing group size results in greater travel costs and competition over depletable food resources, which could lead to reduced individual reproductive success. however, in groups with an increasing number of males, female reproductive success is predicted to augment because larger male groups might better protect immatures from infanticidal attacks. in contrast, male reproductive success is ...200818293377
number and topography of cones, rods and optic nerve axons in new and old world better understand the evolution of spatial and color vision, the number and spatial distributions of cones, rods, and optic nerve axon numbers were assessed in seven new world primates (cebus apella, saimiri ustius, saguinus midas niger, alouatta caraya, aotus azarae, calllithrix jacchus, and callicebus moloch). the spatial distribution and number of rods and cones was determined from counts of retinal whole mounts. optic axon number was determined from optic nerve sections by electron micros ...200818598400
natural plasmodium infections in brazilian wild monkeys: reservoirs for human infections?four hundred and forty-eight samples of total blood from wild monkeys living in areas where human autochthonous malaria cases have been reported were screened for the presence of plasmodium using microscopy and pcr analysis. samples came from the following distinct ecological areas of brazil: atlantic forest (n=140), semideciduous atlantic forest (n=257) and cerrado (a savannah-like habitat) (n=51). thick and thin blood smears of each specimen were examined and plasmodium infection was screened ...200818620330
survey of alouatta caraya, the black-and-gold howler monkey, and alouatta guariba clamitans, the brown howler monkey, in a contact zone, state of rio grande do sul, brazil: evidence for hybridization.sympatry and natural hybridization between howler monkey taxa (alouatta spp.) has only recently being confirmed in the wild. surveys in areas of potential contact between the distribution of two taxa have shown that sympatry is rare, although more common than previously known. here we report the results of a survey conducted in a contact zone between the only two sexually dichromatic howler monkey taxa, alouatta caraya and a. guariba clamitans, in são francisco de assis, state of rio grande do s ...200818654738
genotyping of giardia duodenalis from southern brown howler monkeys (alouatta clamitans) from brazil.giardia duodenalis is a widespread intestinal protozoan that can infect humans and animals, both domestic and wild. independent of host, infections present with the same symptoms. however, based on host specificity, giardia isolates have been grouped into genotypes a to g. parasites of assemblage a and b are known to infect humans, in addition to primates and a wide variety of mammals. in brazil, hitherto giardia genotypes were defined only for humans and domestic animals. to evaluate the genoty ...200818834669
current status of the habitat and population of the black howler monkey (alouatta pigra) in balancán, tabasco, mexico.we evaluated the habitat and populations of the black howler monkey (alouatta pigra) in the municipality of balancán, tabasco, southeastern mexico, using a combination of field surveys and remotely sensed data. we identified 21,937 ha of remnant vegetation composed of 1,348 fragments. fragments separated by up to 200 m were grouped into "clusters" of fragments in accordance with the maximum observed open distance crossed by a. pigra. a total of 11% or 84 of the 772 clusters identified through re ...200818850585
infant hybrids in a newly formed mixed-species group of howler monkeys (alouatta guariba clamitans and alouatta caraya) in northeastern argentina.natural hybridisation between species has been reported in several primate taxa. in the neotropics, there is increasing evidence of this phenomenon in howler monkeys (genus alouatta) in contact zones between species. we describe the first known case of formation of a mixed-species group, and two cases of putative infant hybrids between the brown howler (alouatta guariba clamitans) and the black howler (a. caraya) in misiones, argentina. for 2 years, we followed a group consisting of one adult ma ...200818855099
the karyotype of alouattapigra (primates: platyrrhini): mitotic and meiotic analyses.we describe for the first time the karyotype of the black howler monkey, alouatta pigra. conventional staining, g- and c-banding, and fluorescence in situ hybridization (fish) with a peptide nucleic acid (pna) pantelomeric probe were performed. eight free ranging adult individuals, four males and four females, within the natural distribution of the species presented a diploid karyotype with 2n = 58. mitotic analyses showed an autosomal complement composed of 6 submetacentric, 3 metacentric, and ...200819096205
foraging ecology of howler monkeys in a cacao (theobroma cacao) plantation in comalcalco, mexico.recent evidence indicates that primate populations may persist in neotropical fragmented landscapes by using arboreal agroecosystems, which may provide temporary habitats, increased areas of vegetation, and connectivity, among other benefits. however, limited data are available on how primates are able to sustain themselves in such manmade habitats. we report the results of a 9-month-long investigation of the feeding ecology of a troop of howler monkeys (n = 24) that have lived for the past 25 y ...200616429417
naturally acquired visceral leishmaniasis in non-human primates in brazil.visceral leishmaniasis (vl) is a chronic and often fatal protozoal disease that is endemic in belo horizonte (state of minas gerais, brazil). leishmania sp. is an intracellular obligatory parasite of macrophages that can naturally infect several mammalian species. non-human primates (nhp) have been used as experimental models for infection with leishmania of the donovani complex. the present report describes a case of visceral leishmaniasis in a black-fronted titi. among 41 primates kept in capt ...201020056328
chromobacterium violaceum infection in a free-ranging howler monkey in costa rica.chromobacterium violaceum is a gram-negative saprobe bacterium that is a rare opportunistic pathogen in mammals. there are numerous reports in humans including fatalities, but no record exists in free-ranging nonhuman primates. here we report an infection by c. violaceum in a wild adult male howler monkey (alouatta palliata) captured at ballena marine national park, in southwestern costa rica. the individual had severe skin lesions over its extremities; gross findings included multiple skin ulce ...201020090050
impact of yellow fever outbreaks on two howler monkey species (alouatta guariba clamitans and a. caraya) in misiones, argentina.two yellow fever outbreaks (yfos) occurred in northeastern argentina between november 2007 and october 2008, seriously affecting populations of two howler monkey species: the brown howler alouatta guariba clamitans and the black howler alouatta caraya. both howlers live syntopically in el piñalito provincial park, misiones, where four groups (36 individuals) were studied since january 2005. the first dead howlers were found on january 20, 2008, in el piñalito. systematic searches found 14 dead h ...201020095025
characterizing the reproductive physiology of the male southern black howler monkey, alouatta reproductive data are available for any species of howler monkey, including those listed as threatened (alouatta pigra) and endangered (a. palliata) by the convention on international trade in endangered species status (cites) report. the southern black howler monkey (a. caraya) is being considered as a model species to develop assisted reproductive technology (art) for vulnerable howler species. specific objectives of this study were to evaluate the effect of 1) time of year on ejaculat ...200111330639
parasitic infections of three mexican howler monkey groups (alouatta palliata mexicana) living in forest fragments in order to better understand how patterns of parasitism in howler monkeys are affected by forest fragmentation, we carried out a 1 year survey of gastrointestinal parasites in fecal samples from three groups of mexican howler monkeys inhabiting different forest fragments in the los tuxtlas biosphere reserve, mexico. the study groups were chosen because the conditions in which they lived suggested a potentially negative gradient for parasite richness and a positive gradient for levels of parasit ...201020224913
observed infanticides following a male immigration event in black howler monkeys, alouatta pigra, at palenque national park, mexico.this study describes two cases of directly observed and one case of nearly observed infanticide after an adult male immigrated into a multimale-multifemale group of black howler monkeys (alouatta pigra) at palenque national park, mexico. the immigrant male entered the group alone, injured the central adult male, presumably evicted the noncentral adult male, and killed all three young infants present over the course of three consecutive days in february 2010. three weeks after the infanticide eve ...201020665226
coalescent analysis of mtdna indicates pleistocene divergence among three species of howler monkey (alouatta spp.) and population subdivision within the atlantic coastal forest species, a. guariba.we have used coalescent analysis of mtdna cytochrome b (cyt b) sequences to estimate times of divergence of three species of alouatta--a. caraya, a. belzebul, and a. guariba--which are in close geographic proximity. a. caraya is inferred to have diverged from the a. guariba/a. belzebul clade approximately 3.83 million years ago (mya), with the later pair diverging approximately 1.55 mya. these dates are much more recent than previous dates based on molecular-clock methods. in addition, analyses ...201021107992
molecular evolution of trichromacy in primates.although trichromacy in old and new world primates is based on three visual pigments with spectral peaks in the violet (sw, shortwave), green (mw, middlewave) and yellow-green (lw, longwave) regions of the spectrum, the underlying genetic mechanisms differ. the sw pigment is encoded in both cases by an autosomal gene and, in old world primates, the mw and lw pigments by separate genes on the x chromosome. in contrast, there is a single polymorphic x-linked gene in most new world primates with th ...19989893841
chromosome painting in two genera of south american monkeys: species identification, conservation, and management.cytogenetic studies showed that a number of new world primate taxa, particularly the genera alouatta, aotus, and callicebus, have highly derived karyotypes. cytogenetics in these primates, at every level of analysis, has contributed to the recognition of species and revealed that their number was certainly underestimated by researchers relying solely on traditional morphological data. further attention was drawn to alouatta and aotus because they are characterized by translocations of the y chro ...201121335958
drinking behavior in the black howler monkey (alouatta caraya). 19921612535
genotyping of potentially zoonotic giardia duodenalis from exotic and wild animals kept in captivity in brazil.we have studied the variability of glutamate dehydrogenase (gdh) and small subunit ribosomal (ssu) rrna coding genes of giardia species in fecal samples isolated from wild and exotic animals in brazil, and compared with homologous sequences of isolates from human and domestic animals characterized in previous studies. cysts of giardia duodenalis were obtained from feces of naturally infected monkeys (alouatta fusca) (n=20), chinchillas (chinchilla lanigera) (n=3), ostriches (struthio camelus) (n ...201121530084
oncornavirus particles in lymphoid cultures from a howler monkey with herpesvirus saimiri-induced disease.budding and extracellular oncornavirus particles were observed in cells of lymphoid cultures derived from the spleen, lymph node, and blood of a howler monkey (alouatta caraya) that developed a malignant lymphoproliferative disease after infection with herpesvirus saimiri. the various possible sources of origin of these particles are discussed.1976187783
synteny of human chromosomes 14 and 15 in the platyrrhines (primates, platyrrhini).in order to study the intra- and interspecific variability of the 14/15 association in platyrrhini, we analyzed 15 species from 13 genera, including species that had not been described yet. the dna libraries of human chromosomes 14 and 15 were hybridized to metaphases of alouatta guariba clamitans, a. caraya, a. sara, ateles paniscus chamek, lagothrix lagothricha, brachyteles arachnoides, saguinus midas midas, leontopithecus chrysomelas, callimico goeldii, callithrix sp., cebus apella, aotus nig ...200921637455
impact of intrasexual selection on sexual dimorphism and testes size in the mexican howler monkeys alouatta palliata and a. of the goals of physical anthropology and primatology is to understand how primate social systems influence the evolution of sexually selected traits. howler monkeys provide a good model for studying sexual selection due to differences in social systems between related species. here, we examine data from the sister howler monkey species alouatta palliata and a. pigra inhabiting southeastern mexico and northern guatemala. we use a resampling approach to analyze differences in sexual dimorphis ...201121826636
detection of etiological agents of malaria in howler monkeys from atlantic forests, rescued in regions of são paulo city, some states of the brazilian extra-amazonian region, such as the atlantic forest area, autochthonous human cases of malaria were related to simian malarias and vice versa.201121933192
Variation in the Extraction Efficiency of Estradiol and Progesterone in Moist and Lyophilized Feces of the Black Howler Monkey (Alouatta pigra): Alternative Methods.Several fecal steroid extraction techniques have been developed to measure the ovary function in different species of mammals. However, regardless of the method of extraction and the sample type chosen, it has been observed that they can yield results with different percentages of recuperation. The objective of this study was to determine whether the type of substratum, solvent and extraction method used have any influence on the extraction efficiency in the feces of Alouatta pigra (black howler ...201122194723
Yellow fever outbreak affecting Alouatta populations in southern Brazil (Rio Grande do Sul State), 2008-2009.The natural transmission cycle of Yellow Fever (YF) involves tree hole breeding mosquitoes and a wide array of nonhuman primates (NHP), including monkeys and apes. Some Neotropical monkeys (howler monkeys, genus Alouatta) develop fatal YF virus (YFV) infections similar to those reported in humans, even with minimum exposure to the infection. Epizootics in wild primates may be indicating YFV circulation, and the surveillance of such outbreaks in wildlife is an important tool to help prevent human ...201222020690
molecular typing of giardia duodenalis isolates from nonhuman primates housed in a brazilian zoo.giardia infections in captive nonhuman primates (nhp) housed at a brazilian zoo were investigated in order to address their zoonotic potential. fresh fecal samples were collected from the floors of 22 enclosures where 47 primates of 18 different species were housed. the diagnosis of intestinal parasites after concentration by sedimentation and flotation methods revealed the following parasites and their frequencies: giardia (18%); entamoeba spp. (18%); endolimax nana (4.5%); iodamoeba spp. (4.5% ...201524553608
are howler monkey species ecologically equivalent? trophic niche overlap in syntopic alouatta guariba clamitans and alouatta caraya.according to the principle of competitive exclusion, niche differentiation allows the stable coexistence of closely related species. we analyzed dietary profile and diversity, and dietary overlap between syntopic brown howlers (br; alouatta guariba clamitans) and black and gold howlers (blg; a. caraya) in the atlantic forest of ne argentina, with the objective of evaluating the degree of trophic niche overlap and potential interspecific competition for food. during 12 months, we collected data o ...201019953557
seroprevalence of trypanosoma cruzi and leishmania mexicana in free-ranging howler monkeys in southeastern mexico.natural infection of wild mammals by protozoa parasites is quite common in nature. for neotropical primates different infections of parasites that are etiological agent of disease in human have been identified. in particular, infections by trypanosoma cruzi and leishmania sp., have been reported for some new world primate species, but there are no reports of infection with these parasites in any primate species in mexico. a serological study was conducted on two howler monkey species (alouatta p ...201323165742
pheochromocytoma in six new world primates.six new world primates, including 2 golden lion tamarins (leontopithecus rosalia), 2 cotton-top tamarins (saguinus o. oedipus), 1 black howler monkey (alouatta caraya), and 1 black-handed spider monkey (ateles g. geoffroyi), were diagnosed with unilateral (4/6) or bilateral (1/6) adrenal or extra-adrenal (1/6) pheochromocytoma by light microscopy and immunohistochemical staining for chromogranin a. overt invasive behavior or metastases were not observed in any primate, and thus these neoplasms w ...200919276065
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